Graphical user interface for a portion of a display screen



The FIGURE is a front view of a new graphical user interface for a portion of a display screen showing a new design.

The broken line showing of the outer border of the screen is included for the purpose of illustrating environmental structure and forms no part of the claimed design. The broken lines on the user interface form no part of the claimed design. 

The ornamental design for a graphical user interface on a portion of a display screen, as shown and described. 